JPH07129870A - Gas leak detection device for gas insulated switchgear - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a gas leak detection device for a gas insulated switchgear, which can detect a gas leak and its position at an early stage and can also grasp the degree of the gas leak at an early stage. [Configuration] A gas density sensor 4 provided in each gas compartment 3 of the GIS tank 1 outputs gas density data in each gas compartment 3. The gas density data is the interface device 5
To the data processing device 6 after being encoded and encoded into a predetermined data format. Data processing device 6
Writes the gas density data in the storage device 7. at the same time,
The data processing device 6 reads data from the storage device 7 at regular intervals, linearly approximates the temporal change in gas density, calculates the slope thereof, and compares the slope with a preset slope.
Determine if there is a gas leak. Then, this judgment result is sent to the display device 8 together with the related data and displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preventive maintenance device for a gas-insulated switchgear (GIS) used in electric power equipment and the like, and more particularly to a device for detecting leakage of insulating gas.

[0002]

2. Description of the Related Art A GIS hermetically sealed container is divided into a plurality of gas compartments for a single or a plurality of devices, and an insulating gas is enclosed in each gas compartment. Conventionally, sulfur hexafluoride (SF ₆ ) having a large dielectric strength has been used as an insulating gas for such a GIS. It is enclosed.

On the other hand, the GIS hermetically sealed container has a large number of airtight parts such as O-rings and welding. When gas leakage occurs due to defects or deterioration of these airtight portions, the gas pressure naturally decreases gradually. And
When the gas pressure decreases in this way, the insulation performance of the GIS deteriorates, and in the worst case, it may lead to insulation breakdown and hinder power supply.

From the above, GIS has hitherto been
A gas leak alarm device is provided for detecting a gas leak. This gas leak alarm device generally monitors the gas pressure in the GIS sealed container with a gas pressure gauge attached to the GIS sealed container, and when the gas pressure falls below a certain value, a contact built in the gas pressure gauge is provided. Is activated to give an alarm for notifying a gas pressure drop, that is, a gas leak. As described above, the gas pressure gauge used for the purpose of detecting gas leakage has a temperature sensor and has a function of correcting and displaying the gas pressure at a certain reference temperature (for example, 20 ° C.). With this function, a pressure change due to a temperature change is prevented from being erroneously determined as a gas leak.

[0005] Such a conventional gas leak alarm system, for example, when applied to gas compartment container of the rated gas pressure 4kg · f / cm ^2, an alarm gas pressure setpoint is 3.5kg · f / cm ²
Selected to the degree. The reason for this is as follows. That is, first, the set value error is usually about ± 0.2 kg · f / cm ² . Therefore, the set value is high, for example, 3.8 kg
When set to about f / cm ² , the set value error is +0.2
If it is kg · f / cm ^2, so that the result out alarm at the rated gas pressure 4kg · f / cm ^2. On the contrary, when the set value is low, for example, 3 kg · f / cm ² , the set value error is −
If it is 0.2 kgf / cm ² , the gas leakage will progress considerably when the alarm is issued, and the gas pressure will already be 2.8 kgf.
Since it has fallen to / cm ² , the discovery of gas leaks will be delayed. As described above, the alarm gas pressure set value is usually set to about 3.5 kg · f / cm ² because the inconvenience occurs even if the set value is set high or low.

The operation of the conventional gas leak alarm device as described above is as follows. That is, first, GIS
When the airtight portion of the hermetically sealed container deteriorates, gas leakage occurs, and the gas pressure gradually decreases, the gas pressure gauge of the gas leakage alarm device detects this change in gas pressure. Next, this gas pressure gauge indicates that the gas pressure is at the alarm operation level (alarm gas pressure setting value).
When the temperature drops to 0, an external alarm is issued. Therefore, if each gas pressure gauge is attached to the sealed container of each gas compartment of GIS, it is easy to identify the gas compartment causing the gas leak by knowing which gas pressure gauge has issued the alarm. Can be specified.

[0007] In this way, at the time when the alarm is issued from the gas pressure gauge, the maintenance personnel rushes to the site to check the gas pressure in the gas section concerned, the location of the gas leak, the gas leak rate, etc. Will be investigated. Further, based on the results of these investigations, it will be necessary to make a concrete judgment as to whether or not an emergency response is necessary or whether only emergency treatment is required for the time being, and take appropriate action.

[0008]

By the way, in the conventional gas leak alarm device as described above, the gas leak cannot be detected until the gas pressure is lowered to the alarm operation level and an alarm is issued. In addition, the extent of gas leakage will not be clarified only after inspection and investigation on-site by maintenance personnel, which is carried out after the alarm is issued.
Therefore, the discovery of the gas leak and the grasp of the status are delayed, and the GI
There is a problem that S is likely to cause dielectric breakdown.

The present invention has been proposed in order to solve the problems of the conventional gas leak alarm device as described above, and its purpose is to detect a gas leak and its position at an early stage,
It is an object of the present invention to provide a gas leakage detection device for a gas insulated switchgear, which can grasp the degree of gas leakage at an early stage.

[0010]

A gas leak detection device for a gas insulated switchgear according to the present invention comprises a gas density sensor, a storage means, a calculation means, a determination means, and a display means. Among them, the gas density sensor is individually provided in each gas compartment of the gas insulated switchgear (GIS) and measures the gas density of each gas compartment. The storage means samples the output of the gas density sensor at a preset constant time period, and stores the sampled gas density value and time. The calculating means linearly approximates the temporal change of the gas density value by using the N pieces of data of the gas density value and the time point traced back from the present among the data stored in the storage means, and obtains the slope thereof. The judging means judges the presence or absence of gas leakage by comparing the inclination obtained by the calculating means with a preset constant inclination. The display means displays a gas leak alarm and a gas section corresponding to the gas density sensor when the determination means determines that a gas leak has occurred.

According to a second aspect of the present invention, there is provided a gas leakage detecting device for a gas insulation switchgear, comprising a gas density sensor, a storage means, and a first means.
The calculation means, the first judgment means, the second calculation means, the second judgment means, and the display means. Among these, the gas density sensor and the storage means have the same configuration as the invention of claim 1, and the first calculation means and the first determination means correspond to the calculation means and the determination means of claim 1, respectively. However, the second calculation means, the second determination means, and the display means have the following features.

In other words, the second calculation means, when the judgment other than the occurrence of gas leakage is made by the first judgment means,
Among the data stored by the storage means, the gas density value and the M times of the data, which is more than N times, are used to linearly approximate the temporal change of the gas density value and obtain the slope thereof. Then, the second determination means is set in advance so that the inclination obtained by the second calculation means is gentler than the inclination (first inclination) set as the comparison reference in the first determination means. Compared to the second slope,
Determine if there is a gentle gas leak. Further, the display means corresponds to the gas leak alarm and the gas density sensor when the gas leak is judged to have occurred by either the first judging means or the second judging means. The gas compartment is displayed.

According to a third aspect of the present invention, there is provided a gas leak detection device for a gas insulated switchgear according to the first or second aspect, wherein the display means further has the following features. That is, the display means is configured to display an alarm of gas leak occurrence, the position of the gas section corresponding to the gas density sensor, the value of the slope of the gas density change, and the current gas density value.

A gas leakage detection device for a gas insulated switchgear according to the invention of claim 4 is characterized in that, in the invention of claim 1 or 2, it further comprises a time calculation means and a time display means. Of these, the time calculation means obtains the time for the gas density value to fall to the preset gas density value from the slope of the gas density change, the current time, and the gas density value. The time display means displays the time calculated by the time calculation means.

[0015]

The operation of the gas detecting device of the present invention having the above-mentioned structure is as follows. That is, first, GIS
Suppose a gas leak occurs in a gas compartment with a sealed container. In this case, the gas density in this gas compartment gradually decreases. The state of this decrease in gas density is measured by a gas density sensor provided in the gas compartment,
The gas density value output from the gas density sensor is sampled by the storage means at a preset fixed time period and stored together with the time. Then, the calculation means traces back from the present to the past, for example, using N gas density values from the present to x hours ago, and linearly approximates the temporal change of the gas density based on a method such as the least-squares method. Find the slope. Furthermore, when this inclination, that is, the tendency of the gas density value to decrease, becomes steeper than a certain preset inclination, the determination means determines that gas leakage has occurred.

Particularly, when the first and second calculating means and the first and second determining means are used, the gas leak determination can be performed in two steps. That is, when the inclination obtained by the first calculating means is small and the first determining means makes a determination other than the occurrence of a gas leak, the second calculating means produces more data than the first calculating means. Calculate the slope using the number of samples. Then, when the obtained slope, that is, the decreasing tendency of the gas density value becomes steeper than the second gentler slope set separately, it is determined that gas leakage has occurred by the second determination means. to decide.

As described above, when it is judged by any of the judging means that the gas leakage has occurred,
The display means gives a gas leak alarm and displays the corresponding gas compartment. In general, the display means displays an alarm about the occurrence of a gas leak, the position of the gas compartment corresponding to the gas density sensor, the value of the slope of the gas density change, and the current gas density value.

Further, when the time calculating means and the time displaying means are provided, first, the time calculating means determines the gas density value from the current gas density value and the slope by the "alarm operation" in the conventional gas leak alarm device. Predict the time to drop to "level". Then, the time display means displays the obtained predicted time and the corresponding gas section.

[0019]

【Example】

(1) Configuration of Embodiment FIG. 1 is a configuration diagram showing an embodiment of a gas leakage detection device of a gas insulated switchgear according to the present invention. In the figure, 1 is a GIS tank, and 2 is an insulating spacer for supporting a high-voltage conductor (not shown), which also serves as an airtight partition wall. The GIS tank 1 uses the insulating spacer 2 that also functions as an airtight partition.
It is divided into a plurality of gas compartments 3. An insulating gas, for example, SF ₆ gas is enclosed in each gas compartment 3. The filling pressure of SF ₆ gas is generally 4 kgf
It is about / cm ² . Reference numeral 4 denotes a gas density sensor attached to each gas compartment 3, which outputs gas density data in terms of 20 ° C. Insulating spacer 2, gas compartment 3,
The gas density sensor 4 and the gas density sensor 4 are individually labeled with a, b, c, ... From the viewpoint of emphasizing mutual independence.

Reference numeral 5 in the figure denotes an interface device for inputting and encoding the output of the gas density sensor 4, converting it into a preset data format, and transmitting the data to the data processing device 6 in the next stage. is there. The data processing device 6 is a device that inputs the gas density value of the gas section 3 obtained through the interface device 5 and performs data processing as described later, and corresponds to the calculation means and the determination means of the present invention. Further, in the figure, 7 is a storage device for filing gas density data corresponding to each gas compartment 3 including past values, and 8 is a display device for displaying the processing result of the data processing device 7. It corresponds to the means.

FIG. 2 is a flow chart showing a process executed by the data processing device 6 shown in FIG. (Gas leak occurs) ”, and if“ abnormal (gas leak occurs) ”, a series of processes 10a for displaying the process result on the display device 8,
10b, 11a, 11b, 12a, 12b and 13 are included. The latter series of processing is the first and second reading processing 1
0a, 10b, first and second calculation processes 11a, 11b,
The first and second determination processes 12a and 12b, and the alarm display process 13.

Of these, the first read processing 10a is
This is a process of reading N pieces of past data from the storage device 7, and the first calculation process 11a is the first read process 10
This is a process for obtaining the slope A from the data read in a,
In the first determination processing 12a, the inclination A obtained by the first calculation processing 11a is set to a preset first inclination −K ₁
Compared with the above, when A ≦ −K _1, it is a process of determining that “abnormal (gas leak has occurred)”. In this case, the first slope −K ₁ is the slope of the relatively steep descending slope, and K ₁ is a positive number.

The second read processing 10b is the first read processing.
The determination process 12a, A ≦ -K ₁ is not satisfied,
This is a process of reading M pieces of past data, which is larger than N pieces, from the storage device 7 when it is determined that there is no “abnormality (gas leak occurrence)”, and the second calculation processing 11b is the second
Is a process for obtaining the slope A from the data read by the reading process 10b of the above, and the second determination process 12b uses the slope A obtained by the second calculation process 11b as the preset second slope −K ₂ . By comparison, when A ≦ −K _2, it is a process of determining “abnormality (gas leak occurrence)”. In this case, the second slope −K ₂ is the first slope −K
_The absolute value is smaller than _1, which is a relatively gradual downward slope, and K ₂ is a positive number.

Further, the alarm display processing 13 is "abnormal (gas leakage occurs)" when the first determination processing 12a or the second determination processing 12b determines "abnormal (gas leakage generation)". In this processing, the judgment result is sent to the display device 8 to display the alarm of gas leak occurrence and the corresponding gas section.

(2) Operation of the Embodiment The operation of this embodiment having the above-mentioned structure is as follows.

First, the gas density sensor 4 attached to each gas compartment 3 of the GIS tank 1 measures the pressure in each gas compartment 3 and converts the pressure value into a temperature of 20 ° C., that is, gas density data. Output. The gas density data of each gas section 3 output in this way is input to the interface device 5. In this interface device 5, the gas density data from each gas density sensor 4 is encoded, converted into a preset data format, and transmitted to the next data processing device 6.

In the subsequent data processing device 6, data processing is performed according to the flowchart shown in FIG. That is, each gas section 3 input from the interface device 5
The gas density data of 1 is sequentially written to the storage device 7 by the data writing process 9 together with the gas section position data and the time data at a certain fixed cycle, for example, a 1-minute cycle.

On the other hand, the first reading process 10a reads N data (N days) of a certain fixed period, for example, a one-day period, from the storage device 7 by going back from the present to the past. In the first calculation processing 11a, the first reading processing 1
Using the N data read by 0a, the temporal change of the gas density of each gas section 3 from the past to the present is linearly approximated by the least square method, and the slope A thereof is calculated. Next, the first determination process 12a causes the slope A obtained in the first calculation process 11a to be steeper than the relatively steep descending slope −K ₁ (where K ₁ is a positive number). It is determined whether or not, that is, whether A ≦ −K ₁ holds.

In this first judgment processing 12a, A≤
When -K ₁ is satisfied and it is determined that "abnormal (gas leak has occurred)", the alarm display processing 13 causes the display device 8 to display this "abnormal (gas leak)" determination result together with related data. Send and display. Specifically, the display device 8 displays a gas leak occurrence alarm, the position of the gas compartment, the value of the slope of the gas density change, and the current gas density value, and a relatively rapid gas leak occurs in the gas compartment. The occurrence is reported to the outside. Then, the data processing device 6 once completes the processing by the alarm display processing 13 (first processing route: a processing route when a relatively rapid gas leak occurs).

On the other hand, in the first judgment processing 12a, when A ≦ −K ₁ is not established, the process immediately moves to the second reading processing 10b and the first reading processing 10a.
The data of M data, which is more than N data, is read further back in time than the time read by. Second calculation process 11b
Then, by using the M pieces of data read by the second reading process 10b, each gas section 3 by the least squares method.
The time-dependent change in the gas density of the above from the present to the present is linearly approximated, and the slope A thereof is calculated. Next, by the second determination processing 12b, the slope A obtained in the second calculation processing 11b is the slope -K ₂ (where K
₂ is a positive number), that is, A ≤
-It is determined whether K ₂ holds.

In this second judgment processing 12b, A≤
If -K ₂ is satisfied and it is determined that "abnormal (gas leak has occurred)", the alarm display processing 13 causes the display device 8 to display this "abnormal (gas leak)" determination result together with related data. Send and display. Specifically, the display device 8 displays a gas leak occurrence alarm, the position of the gas compartment, the value of the slope of the gas density change, and the current gas density value, indicating that a relatively gentle gas leak occurs in the gas compartment. The occurrence is reported to the outside. Then, the data processing device 6 once completes the processing by the alarm display processing 13 (second processing route: a processing route when a relatively moderate gas leak occurs).

On the other hand, in the second judgment processing 12b, when A ≦ −K ₂ is not established, it is judged to be “normal (no gas leakage occurs)” and the processing is temporarily completed at that time (first (3) processing route: a processing route at normal time)

One of the above three processing routes is once completed to be processed, and after a certain period of time, returning to the first reading process 10a is defined as one cycle. For example, the gas leak detection process is repeated every day.

(3) Effects of the Embodiment As described above, according to this embodiment, by monitoring the slope of the decrease of the gas density from a certain point in the past to the present, when a gas leak occurs. Can detect gas leakage at a stage where the cumulative amount of gas leakage is small. Moreover, the gas section of the GIS causing the gas leakage can be quickly grasped from the mounting position corresponding to the gas density sensor showing the downward tendency. Further, the gas leak rate can be quickly grasped from the current gas density value and the value of the descending slope. Therefore, when a gas leak occurs, you can quickly and surely grasp the detailed situation of the gas leak,
It becomes possible to take appropriate actions at an early stage.

Particularly, in this embodiment, since the inclination of the decrease of the gas density is judged at two levels,
In addition to being able to quickly detect relatively rapid gas leaks that require immediate attention, it is also possible to quickly detect relatively slow gas leaks that do not require immediate action. It is possible to clearly understand the difference in the degree of gas leakage at two levels. As a result, it becomes easy to appropriately select a countermeasure according to the degree of gas leakage. Furthermore, for a gas leak with a relatively gradual decrease in the slope of the gas density, it is possible to detect it more accurately by increasing the number of data M for judging the slope.

(4) Other Embodiments Note that the present invention is not limited to the above-mentioned embodiment, and it is possible to judge the slope of the decrease in gas density at three or more levels. In this case, more detailed detection can be performed. On the contrary, it is also possible to judge the slope of the decrease of the gas density in only one step, and in this case, the entire process can be simplified.

Further, in the above-mentioned embodiment, the method of grasping the degree of gas leakage from the current gas density value and the value of the descending slope is adopted. It is also possible to perform a process of predicting the time to reach the alarm operation level by using the density value and the value of the falling slope. In this case, the data processing device 6 sends the data of the obtained time to the display device 8 together with the determination result of "abnormality (gas leak occurrence)" and displays these data. With this configuration, the degree of gas leakage can be directly grasped by the length of time displayed by the display device 8.

[0038]

As described above, according to the gas leakage warning device of the gas insulated switchgear according to the present invention, the gas leakage of the gas insulated switchgear and its position can be reliably detected at an early stage when the cumulative gas leakage amount is small. The degree of gas leakage can be grasped at an early stage. Further, when the determination of the slope of the gas density is made at two or more levels, it is possible to accurately detect a wide range of gas leaks from a moderate gas leak to a rapid gas leak. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a gas leakage detection device of a gas insulated switchgear according to the present invention.

FIG. 2 is a flowchart showing a process executed by the data processing device 6 shown in FIG.

[Explanation of symbols]

 1 ... GIS tank 2 ... Insulating spacer 3 ... Gas section 4 ... Gas density sensor 5 ... Interface device 6 ... Data processing device 7 ... Storage device 8 ... Display device 9 ... Writing process 10 ... Read process 11 ... Calculation process 12 ... Judgment process 13 ... Alarm display processing

Claims (4)

[Claims] 1. A gas density sensor, which is individually provided in each gas compartment of a gas-insulated switchgear divided into a plurality of gas compartments, for measuring the gas density of each gas compartment, and outputs of the gas density sensor in advance. Storing means for sampling at a set fixed time period and storing the sampled gas density value and time, and N of the gas density value and time going back from the present to the past among the data stored in the storage means. Using the individual data, the time-dependent change of the gas density value is linearly approximated, and the slope obtained by the calculation means and the slope obtained by the calculation means are compared with a preset constant slope, Judgment means for judging the presence or absence of leakage, and when the judgment means judges that gas leakage has occurred, an alarm of gas leakage occurrence, and a gas compartment corresponding to the gas density sensor. And having display means for displaying, a gas leakage detection system of the gas insulated switchgear. 2. A gas density sensor that is individually provided in each gas compartment of a gas insulated switchgear that is divided into a plurality of gas compartments and that measures the gas density of each gas compartment, and outputs of the gas density sensor in advance. Storage means for sampling at a set fixed time period and storing the sampled gas density value and time, and N of the gas density value and time going back from the present to the past among the data stored in the storage means. The linear change of the gas density value with time is calculated using the data of
And a first determining means for comparing the inclination obtained by the first calculating means with a preset first inclination to determine the presence or absence of gas leakage, and the first determining means. When the means other than the gas leak occurrence is determined by the means, the gas density value and the time M of the data stored in the storage means, which is more than the N data, are used to calculate the gas. Second calculation means for linearly approximating the temporal change of the density value and obtaining the slope thereof, and the slope obtained by the second calculation means are set in advance so as to be gentler than the first slope. A second determination means for determining the presence or absence of a gradual gas leak, as compared with the second inclination, and a gas leak occurring due to any of the first determination means and the second determination means. If it is determined that A gas leak detection device for a gas insulated switchgear, comprising: a live alarm and a display means for displaying a gas compartment corresponding to the gas density sensor. 3. The display means is an alarm for gas leak occurrence,
Gas according to claim 1 or 2, characterized in that it is arranged to display the position of the gas compartment corresponding to the gas density sensor, the value of the slope of the gas density change and the current gas density value. Gas leak detector for insulation switchgear. 4. A time calculating means for obtaining a time required to decrease to a preset gas density value from a slope of a change in gas density, a current time and a gas density value, and the time obtained by the time calculating means is displayed. The gas leak detection device for a gas insulated switchgear according to claim 1 or 2, further comprising: a time display means.